Method and an Apparatus for Processing an Audio Signal

1. A method for processing an audio signal, comprising: receiving the audio signal; and, processing the received audio signal, wherein the audio signal is processed according to a scheme comprising: comparing a size information of at least two blocks of A+1 level with a size information of a block of A level corresponding to the at least two of A+1 level; and, determining the at least two blocks of A+1 level as an optimum block if the size information of the at least two blocks of A+1 level is less than the size information of the block of A level, and determining the block of A level as the optimum block if the size information of the block of A level is less than the size information of the at least two blocks of A+1 level.

2. The method of claim 1 , wherein the size information corresponds to one of a coding result, a bit size, and a coded data block.

3. The method of claim 1 , wherein the block of A level corresponds to a combination of at least two the blocks of A+1 level.

4. The method of claim 3 , wherein the hierarchical structure have at least two levels, and block length of a highest level corresponds to integral multiple of block length of a lowest level.

5. The method of claim 4 , wherein the hierarchical structure have six levels, and the block length of the highest level corresponds to 32 multiple of the block length of the lowest level.

6. The method of claim 1 , wherein the size information of at least two blocks of A+1 level corresponds to a sum of a size of one block of A+1 level and a size of next block of A+1 level.

7. The method of claim 1 , further comprising: comparing a size information of at least blocks of A level with a size information of a block of A−1 level if the size information of the at least two blocks of A+1 level is greater than the size information of the block of A level.

8. The method of claim 7 , further comprising: determining the at least two blocks of A level as an optimum block if the size information of the at least two blocks of A level is less than the size information of the block of A−1 level.

9. A non-transitory computer-readable medium having instructions stored thereon, which causes the processor to perform operations, comprising: comparing a size information of at least two blocks of A+1 level with a size information of a block of A level corresponding to the at least two of A+1 level; and, determining the at least two blocks of A+1 level as an optimum block if the size information of the at least two blocks of A+1 level is less than the size information of the block of A level, and determining the block of A level as the optimum block if the size information of the block of A level is less than the size information of the at least two blocks of A+1 level.

10. An apparatus for processing an audio signal, comprising: a initial comparing part comparing a size information of at least two blocks of A+1 level with a size information of a block of A level corresponding to the at least two of A+1 level; and, a conditional comparing part determining the at least two blocks of A+1 level as an optimum block if the size information of the at least two blocks of A+1 level is less than the size information of the block of A level, and determining the block of A level as the optimum block if the size information of the block of A level is less than the size information of the at least two blocks of A+1 level.

11. The method of claim 1 further comprising: determining lag information based on autocorrelation function of the audio signal including the optimum block; and, estimating long-term prediction filter information based on the lag information.

12. The method of claim 11 , further comprising: estimating bitrates of the audio signal after estimating the long-term prediction filter information; and encoding the lag information and the long-term prediction filter information as a side information based on the estimated bitrates.

13. The apparatus of claim 10 further comprising: a lag information determining part determining lag information based on autocorrelation function of the audio signal including the optimum block; and, a filter information estimating part estimating long-term prediction filter information based on the lag information.